Organic light emitting diode display compensation tool

ABSTRACT

A portable information handling system integrated organic light emitting diode (OLED) display presents a compensation image having pixels illuminated at predetermined color and luminance settings. The compensation image is captured by a external camera as a calibration image and analyzed to compare pixel color and luminance provided by the OLED display with expected color and luminance to determine pixel compensation values that correct the OLED display for presentation of a uniform visual image that reproduces an intended visual image when the compensation values are applied at presentation of visual images by the OLED display.

CROSS REFERENCE TO RELATED APPLICATIONS

U.S. Patent Application No. ______, entitled “Organic Light EmittingDiode Display Power Management Based on Usage Scaling” by inventors AsimM. Siddiqui, Deeder M. Aurongzeb, and Jong Seo Lee, Attorney Docket No.DC-116159.01, filed on even date herewith, describes exemplary methodsand systems and is incorporated by reference in its entirety.

U.S. Patent Application No. ______, entitled “Organic Light EmittingDiode Display Thermal Management” by inventors Jong Seo Lee, Deeder M.Aurongzeb, and Asim M. Siddiqui, Attorney Docket No. DC-116163.01, filedon even date herewith, describes exemplary methods and systems and isincorporated by reference in its entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates in general to the field of portableinformation handling systems, and more particularly to an informationhandling system organic light emitting diode display compensation tool.

Description of the Related Art

As the value and use of information continues to increase, individualsand businesses seek additional ways to process and store information.One option available to users is information handling systems. Aninformation handling system generally processes, compiles, stores,and/or communicates information or data for business, personal, or otherpurposes thereby allowing users to take advantage of the value of theinformation. Because technology and information handling needs andrequirements vary between different users or applications, informationhandling systems may also vary regarding what information is handled,how the information is handled, how much information is processed,stored, or communicated, and how quickly and efficiently the informationmay be processed, stored, or communicated. The variations in informationhandling systems allow for information handling systems to be general orconfigured for a specific user or specific use such as financialtransaction processing, airline reservations, enterprise data storage,or global communications. In addition, information handling systems mayinclude a variety of hardware and software components that may beconfigured to process, store, and communicate information and mayinclude one or more computer systems, data storage systems, andnetworking systems.

Portable information handling systems integrate processing components, adisplay and a power source in a portable housing to support mobileoperations. Portable information handling systems allow end users tocarry a system between meetings, during travel, and between home andoffice locations so that an end user has access to processingcapabilities while mobile. Tablet configurations typically expose atouchscreen display on a planar housing that both outputs information asvisual images and accepts inputs as touches. Convertible configurationstypically include multiple separate housing portions that rotationallycouple to each other so that the system converts between closed and openpositions. For example, a main housing portion integrates processingcomponents and a keyboard and rotationally couples with hinges to a lidhousing portion that integrates a display. In a clamshell configuration,the lid housing portion rotates approximately ninety degrees to a raisedposition above the main housing portion so that an end user can typeinputs while viewing the display. In a tablet configuration, the housingportions rotate 360 degrees relative to each other to expose the displayfor touch inputs while the keyboard is hidden at the bottom of thesystem. After usage, convertible information handling systems rotate thelid housing portion over the main housing portion to protect thekeyboard and display, thus reducing the system footprint for improvedstorage and mobility.

Recently, portable information handling systems have begun transitioningfrom integrating liquid crystal displays (LCDs) to instead integrateorganic light emitting diode (OLED) displays. LCDs generate visualimages by passing illumination from a backlight through an array ofpixels that filter red, green and blue light. In contrast, OLED displaysgenerate visual images by creating illumination with direct currentapplied to red, green and blue OLED material of each pixel. Oneadvantage of OLED displays is that generating visual images without abacklight tends to decrease the thickness of the display panel. Anotheradvantage of OLED displays is that the display material integrates in aflexible film that can fold over housing structures. One example systemhas an OLED display film folded over a housing portion so that a displaysurface presents visual images at opposing sides of the housing portion.Another way that an OLED foldable display film integrates in aninformation handling system is to fold at a hinge location so that thedisplay can present a flat tablet appearance with a relatively largesurface area or can fold in a clamshell position to hold part of thedisplay in a raised viewing position.

Although OLED display films offer increased flexibility for integrationof a display in a portable information handling system, OLED displayoperations tend to introduce thermal and power management challenges.Generally, OLED material creates greater illumination by increasingcurrent applied to the OLED material. Applying different amounts ofcurrent to red, green and blue OLED material of a pixel generates aunique color and luminance with varied brightness of red, green and bluelight resulting from each OLED material. The different currents arescanned across OLED pixels at a refresh rate applied by a timingcontroller (TCON) of the display. The TCON sets the current levels basedupon pixel values defined by a graphics controller, which creates thepixel values to define a visual image across the array of OLED pixels.However, OLED material tends to degrade over time so that, as the OLEDpixels are used, different levels of current are needed to create adesired illumination. To achieve a desired presentation of visual imagesat an OLED display, a compensation table is typically maintained thatadjusts the amount of current applied at each pixel for the degradationat each pixel. Degradation of OLED material in each pixel is estimatedbased upon the type of visual images presented by each pixel over time,such as the color and luminance at each pixel. As a result of variationsin current applied to pixels to obtain desired illumination at eachpixel, irregularities in thermal distribution and power consumption canresult. In addition, degradation of OLED material can result in ghostingof visual images at the display where compensation estimated over timedoes not match the actual impact of OLED material degradation on visualimage creation.

Integration of OLED display films into a convertible informationhandling system introduces additional challenges, especially where theOLED display film is disposed on opposing faces of the housing. Forinstance, the angle at which an end user views the display may varybased upon the rotational orientation of the rotationally coupledportable housing portions. In some rotational orientations, some partsof the display surface may have more prominent end user interactionsthan other parts. Further, as the portable housing moves to varyinglighting conditions, such as with different ambient lightcharacteristics, display color and luminance may have to change tomaintain a consistent appearance of presented visual images for the enduser. As display pixels respond to varying conditions, thermal and powermanagement difficulties tend to arise, especially where display pixelcompensation is less accurate. In addition, image ghosting may becomemore distinct and variable since thermal and power variations impactillumination from OLED material in a variable manner as the OLEDmaterial degrades.

SUMMARY OF THE INVENTION

Therefore, a need has arisen for a system and method which manages powerand thermal conditions at an organic light emitting diode (OLED)display.

A further need exists for a system and method that adapts compensationat an OLED display over time with measurements of degradation at theOLED material.

In accordance with the present invention, a system and method areprovided which substantially reduce the disadvantages and problemsassociated with previous methods and systems for management of OLEDdisplay power, thermal and degradation constraints. An OLED display isdivided into plural zones of plural pixels to present visual images ineach zone with adjustments to color and brightness that achieve desiredpower, thermal and degradation constraints. Based upon variouspredetermined conditions, pixels in different display zones may presentvisual images with full or partial pixel density, base commanded orreduced brightness, base commanded scan rate or reduced scan rate, orother display zone individualized presentation parameters.

More specifically, an information handling system processes informationwith a processor that executes instructions in cooperation with a memorythat stores the information and instructions. A graphical processingunit further processes the information to define visual images withpixel values that command the color and luminance generated byapplication of current to OLED material of each pixel. A display zonemanager executing on the information handling system, such as withembedded code stored in non-transitory memory to execute on an embeddedcontroller or graphics processor, defines plural display zones of pluralcontiguous OLED pixels at the display based upon one or morepredetermined conditions, such as power constraints, thermal constraintsand/or OLED material preservation. Based upon the detected condition,pixels of a display zone have illumination adjusted to achieve power,thermal and/or OLED material preservation goals. As an example, adisplay zone that presents passive or background content is adjusted togenerate visual images with a partial pixel density while a display zonewith active content is presented with full pixel density. For instance,partial pixel density places at least some OLED pixels in the displayzone in an off state to reduce power consumption and thermal energygeneration without undue impact on visual image presentation while fullpixel density presents visual images at a base commanded color andluminance. As another example, a pixel refresh rate is reduced in adisplay zone having a static or passive content to reduce powerconsumption and thermal energy release. In one embodiment, compensationvalues that adjust current applied to OLED material in pixels arevalidated by comparing a compensation image presented by the OLEDdisplay against a camera picture image captured of the display.

The present invention provides a number of important technicaladvantages. One example of an important technical advantage is that anOLED display adapts to present visual images at different display zonesto achieve power, thermal and OLED material preservation objectives. Byadjusting pixel density, refresh rate and other visual imagepresentation parameters in passive content display zones, powerconsumption, thermal energy release and OLED material degradation may bereduced. Graduated adjustments at passive content display zones provideadjustments that have minimal impact on the end user experience and inan imperceptible manner. Visual image compensation, which impacts powerand thermal constraints as well as image ghosting, is updated bycapturing a picture with an external camera of a defined compensationimage to compare the base commanded visual image applied to the displaywith the actual illumination presented by the display so thatcompensation values adjust to present more accurate representations ofbased commanded visual images without ghosting effects.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention may be better understood, and its numerousobjects, features and advantages made apparent to those skilled in theart by referencing the accompanying drawings. The use of the samereference number throughout the several figures designates a like orsimilar element.

FIG. 1 depicts an exploded view of a convertible information handlingsystem having a folded organic light emitting diode (OLED) displaydisposed over a housing portion to present visual images at opposingsides of the housing portion;

FIG. 2 depicts a block diagram of an information handling systemconfigured to manage power and thermal constraints related to OLEDdisplay presentation of visual images;

FIG. 3 depicts a flow diagram of a process for adjusting visual imagepresentation to achieve power and thermal management objectives;

FIG. 4 depicts a flow diagram of a control process for adjusting powerapplied for presentation of visual images based upon housing rotationalorientations;

FIG. 5 depicts an example of an OLED display with display zones havingcontent and power management configurations;

FIG. 6 depicts a flow diagram of a process for managing informationhandling system skin temperature by adjusting display zone pixelillumination;

FIG. 7 depicts a flow diagram of a process for managing presentation ofghost images at an OLED display by adjusting color presented at thedisplay; and

FIG. 8 depicts a flow diagram of a process for adjusting thermal and orpower constraints associated with an OLED display by adjusting perceivedbrightness at the display.

DETAILED DESCRIPTION

An organic light emitting diode (OLED) display in a portable informationhandling system adapts power and thermal management to operatingconditions with measured adjustments to OLED material degradation overtime. For purposes of this disclosure, an information handling systemmay include any instrumentality or aggregate of instrumentalitiesoperable to compute, classify, process, transmit, receive, retrieve,originate, switch, store, display, manifest, detect, record, reproduce,handle, or utilize any form of information, intelligence, or data forbusiness, scientific, control, or other purposes. For example, aninformation handling system may be a personal computer, a networkstorage device, or any other suitable device and may vary in size,shape, performance, functionality, and price. The information handlingsystem may include random access memory (RAM), one or more processingresources such as a central processing unit (CPU) or hardware orsoftware control logic, ROM, and/or other types of nonvolatile memory.Additional components of the information handling system may include oneor more disk drives, one or more network ports for communicating withexternal devices as well as various input and output (I/O) devices, suchas a keyboard, a mouse, and a video display. The information handlingsystem may also include one or more buses operable to transmitcommunications between the various hardware components.

Referring now to FIG. 1, an exploded view of a convertible informationhandling system 10 depicts a folded organic light emitting diode (OLED)display 36 disposed over a housing portion 16 to present visual imagesat opposing sides of the housing portion. In the example embodiment,convertible information handling system 10 is built into a portablehousing 12 having a main housing portion 14 and lid housing portion 16rotationally coupled with a hinge 18. For instance, housing 12 rotatesfrom a closed position having lid housing portion 16 proximate to mainhousing portion 14 to a clamshell position having lid housing portion 16raised substantially perpendicular to main housing portion 14. In oneembodiment, housing 12 rotates to a tent position having approximately270 degrees of rotation and a tablet position having a full 360 degreesof rotation. At the varied rotational orientations, folded OLED displayfilm 36 has different display surfaces exposed at different orientationsrelative to the end user and varied ambient conditions, such as externallighting and the external environment for thermal rejection. That is, aslid housing portion 16 raises away from main housing portion 14, greatersurface exposure to external conditions improves thermal rejection forfolded OLED display 36. In one alternative embodiment, a second foldedOLED display film 36 may be disposed over main housing portion 14 to actas a display and input/output device, such as by presenting a virtualkeyboard to accept key input values.

Information handling system 10 processes information with processingcomponents disposed in main housing portion 14. The example embodimentdepicts a motherboard 20 coupled to main housing portion 14 to supportand interface the processing components, such as through wirelines of aprinted circuit board. A central processing unit (CPU) 22 couples tomotherboard 20 and interfaces with random access memory (RAM) 24 toexecute instructions that process information, with the instructions andinformation stored in RAM 24. A chipset 26 interfaces with CPU 22 tomanage CPU clock and communication functions. A graphics processor unit(GPU) 28 interfaces with CPU 22 to accept information for presentationat folded OLED display 36 and process the information into pixel valuesthat define color and luminance of pixels of folded OLED display film36, as is described in greater detail below. An embedded controller (EC)30 manages operation of physical components on motherboard 20, such asfor application of power and thermal transfer systems. A solid statedrive (SSD) 32 stores information in non-transitory flash memory orother persistent storage to retain the information during periods of nopower. For example, SSD 32 stores an operating system and applicationsthat execute on CPU 22 to process information that generates visualimages at folded OLED display film 36. A wireless network interface card(WNIC) 34 interfaces with CPU 22 to support network communications, suchas wireless local area network (WLAN) communications like WiFi andwireless personal area network (WPAN) communications like Bluetooth. Insome example embodiments, WNIC 34 may support wired communications asmay a USB or similar cable port.

Folded OLED display film 36 interfaces with GPU 28 to accept pixelvalues for presentation as visual images. In the example embodiment,folded OLED display film 36 folds over top of lid housing portion 16 toexpose a display surface on opposing sides of lid housing portion 16. Acamera 39 is aligned to capture pictures of visual images facing thedisplay surfaces, such as to support video conferencing. In variousembodiments, folded OLED display film 36 presents various types ofvisual images, typically based upon end user selections and preferences.An active content window 38 presents information selected by the enduser to interact with inputs made by the end user, such as through akeyboard or mouse. In alternative embodiments, the end user may selectactive content window 38 to expand for presentation of visualinformation across the entire display surface. In the exampleembodiment, a passive content window 40 presents other visual imagesthat are not actively associated with end user inputs. In a typical useenvironment, passive content window 40 presents information of anapplication instance as a background under active content window 38 thatan end user may select with a mouse click to bring the information intofocus to accept inputs so that the end user can rapidly change betweenapplications and/or application instances. A background visual image 42presents a default image where other content is not selected, such as ascreensaver, wallpaper or default color. A tool bar 44 with a variety oftool icons 46 are presented along the bottom edge of OLED display film36, such as quick start icons for applications and operating systemfunctions.

Referring now to FIG. 2, a block diagram depicts an information handlingsystem 10 configured to manage power and thermal constraints related toOLED display presentation of visual images. A hardware layer 52 includeshardware components that cooperate to process and present information asvisual images. For example, CPU 22 executes instructions that createvisual information, which GPU 28 further processes into pixel valuesthat define a visual image. The pixel values are provided to a timingcontroller (TCON) 50, which scans the pixel values for application atOLED display 36. The example embodiment depicts OLED display 36 ashaving plural pixels 60 disposed under a cover glass 58 in an array ofpixel columns 68 and pixel rows 70. Each pixel 60 includes red OLEDmaterial 62, blue OLED material 64 and green OLED material 66. TCON 50scans pixel values across pixel columns 68 and along pixel rows 70 toapply current at each of red, blue and green materials so that a colorof a commanded brightness results at each pixel. The scan of pixelvalues takes place at a refresh rate that creates a visual image so thatan end user cannot detect changes over time. For instance, a scanrefresh rate of approximately 60 Hz will typically support a movingvisual image without an end user perceiving the changing pixels due tochanges in pixel values, such as can show up in ghosts of moving images.Lower scan refresh rates of as low as 10 Hz may provide a satisfactoryimage quality where movement is minimal. Thermal sensors 88 are disposedwithin display 36 to monitor thermal conditions related to thepresentation of visual images and report the thermal conditions toembedded controller 30. Since OLED material generates illuminationthrough dissipation of power, thermal conditions may vary across display36 depending upon the color and luminance generated at each pixel. Anangle sensor 48 detects relative rotational orientation of housingportions of information handling system 10. Angle sensor 48 may be aHall sensor or other physical device that monitors hinge position, or aset of accelerometers that measure orientation of the housing portionsrelative to gravity.

Information handling system 10 includes a firmware layer 54 havingembedded code stored in non-transitory flash memory to execute onprocessing components of hardware layer 52. For example, firmwareembedded code is installed and managed as drivers by an operating system78 of a software layer 56. A power manager 72 executes on embeddedcontroller 30 to monitor power use of hardware layer 52. For example,power manager 72 coordinates application of power available from acharger at variable levels demanded by CPU 22 based upon availability ofbattery charge and/or an external power source. A display zone manager74 monitors operating conditions at information handling system 10 todefine plural display zones of contiguous pixels 60 of display 36 formanagement of visual image presentation as is addressed in greaterdetail below. For instance, display zone manager 74 executes on CPU 22,GPU 28 and embedded controller 30 to define display zones based uponpresented content, environmental conditions, housing position, powerconsumption and thermal conditions. A compensation table 76 stored innon-transitory memory includes compensation values for pixels 60 thatadjust pixel values based upon degradation of OLED material over time.The compensation values are estimated based upon the response of theOLED material to current, such as with periodic calibration processes,and based upon tracking of images presented at display 36 and knowndegradation characteristics. For instance, blue OLED material tends todegrade more quickly than red and green OLED material. The compensationvalues may be applied by various hardware components, such as GPU 28 orTCON 50, so that pixels 60 have current applied to generate an intendedcolor and brightness instead of a degraded color and brightness thatwould result from application of a base uncompensated pixel value.

Software layer 56 includes an operating system 78, such as WINDOWS, thatprovides logical interfaces for applications to access resources offirmware layer 54 and hardware layer 52. For example, operating system78 includes a display driver 80 having embedded code distributed asfirmware to interact with GPU 28 for control of operation of display 36.For example, display driver 80 accepts display settings 82, such as froma display control panel of operating system 78, and applies the displaysettings through GPU 28 for effect at display 36. For example, end usercolor, contrast and brightness display settings are applied by displaydriver 80 to determine a base value for pixels 60, such as what would beused by a liquid crystal display that does not experience pixel materialdegradation. Once GPU 28 determines the base pixel values, each pixelvalue is further compensated based upon compensation values ofcompensation table 76 to present the desired image with display 36 atits degraded pixel state. In addition to other applications, softwarelayer 56 includes a compensation image generator 84 and a compensationengine 86. As is described in greater detail below, compensation imagegenerator 84 creates a compensation image for presentation on display 36that presents defined pixel values for a calibration process bycompensation engine 86 to update compensation values of compensationtable 76.

In operation, display zone manager 74 monitors power, thermal and otherconditions at information handling system 10 to adjust visual imagespresented at display 36 to achieve desired presentation, power andthermal constraints. Display zone manager 74 divides display 36 intoplural display zones that each have plural contiguous pixels based uponconditions detected at display 36. As one example, display zones may bedefined to include pixels that present active content as one displayzone, passive content as another zone, background as another displayzone and a tool bar as another display zone. In another exampleembodiment, display zone manager 74 defines display zones based uponrotational orientation of housing portions and the relative position ofdisplay 36 to an anticipated position of an end user. For instance, adisplay portion folded on a housing portion that is rotated to have onesurface towards an end user and the other hidden may be divided intofirst and second zones based on orientation with additional zonesdefined based on content as described above. In one alternativeembodiment, display zone manager 74 defines zones based upon thermalconditions detected by thermal sensors 88, such as by identifyingportions of display 36 that have nonuniform temperature distributions.In another alternative embodiment, display zones may be defined basedupon degradation and associated compensation values, such as to providedegradation leveling on a zone basis while achieving thermal and/orpower management constraints. In various alternative embodiments,different types of display zones of varying size and dimensions may bedefined to achieve desired control so that pixels 60 in each defineddisplay zone are individually managed to achieve the desired control.

Once display zone manager 74 defines display zones to achieve a desiredobjective, adjustments defined by display zone manager 74 are applied ateach pixels of each display zone by GPU 28, such as with alterations tocompensation table 76 that include the adjustments. Pixels in an activedisplay zone present visual images at a full density, meaning that thepixels all illuminate at a base compensated value that generates avisual image as commanded from the operating system and corrected by thecompensation values of compensation table 76. Pixels in non-activedisplay zones present visual images with a partial pixel density,meaning that some of the pixels, such as half, illuminate at the basedcompensated pixel value while the rest of the pixels apply an adjustedpixel value, such as an off state, a reduced brightness state or areduced refresh rate state. In one example embodiment, power managementis achieved by reducing power drawn by pixels 60 in display zones havingless demanding display constraints. For instance, in a display zoneassociated with a passive content or background, power is reduced byplacing at least some of the pixels 60 into an off state having nocurrent applied. Alternatively, some of the pixels may have a reducedbrightness that uses less current or a reduced refresh rate, which alsodecreases power consumption. In an Ultra High Definition (UHD) displayhaving 4,000 (4K) pixels, applying an off state, reduced brightness orreduced refresh rate at every other pixel along a scan will decreasepower consumption with minimal impact on the presentation of visualimages. For example, an active content display zone may present visualimages with all pixels at the base compensated pixel values while abackground display zone presents a background visual image with everyother pixel illuminated so that the overall presentation of visualimages has a minimal and even imperceptible impact on the end userexperience. Within the display zone, the pixels 60 selected for the offstate may alternate so that degradation across the display zone pixelshas an even impact over time. In some embodiments, the partial pixeldensity may include more than half or less than half of the pixels inthe display zone.

Another example of an objective associated with defined display zones isa thermal objective. As OLED material dissipates power to generateillumination, excess thermal energy created with the illuminationresults in an increase to the skin temperature of information handlingsystem 10, which generally must be rejected to the external environmentto avoid excessive skin temperatures. Within an OLED display film, thethermal energy generated at different pixels may vary substantiallydepending upon the color and brightness of each pixel. Display zonemanager interfaces with thermal sensors 88 to detect thermal conditionsand adjust power applied in display zones to achieve a desired thermalconstraint, such as a uniform thermal distribution across the display.For instance, if a housing orientation places a display portion out ofend user view as determined by angle sensor 48, a change to the refreshrate in the hidden display zone can increase or decrease thermal energyreleased by the pixels of the display zone. Since the current applied ata pixel, and thus the thermal energy released, varies depending uponcompensation applied to the pixel from the compensation table, thecompensated value is used to determine thermal management. As anexample, a convertible information handling system having a folded OLEDdisplay disposed on opposing sides of a housing portion may apply visualimages on a hidden display zone that improves the uniformity of thermaldistribution as an adjustment to thermal release at an active displayzone on the opposing side of the housing portion.

In various embodiments, partial pixel densities in a display zone may beapplied in various ways that help to minimize the impact on an end userexperience and improve the life of OLED material. As one example, bluepixel illumination is reduced in a passive or background content displayzone by gradually transitioning blue out of the pixels to increase thepresentation of green illumination. For instance, a timer is referencedwhile the pixel values are gradually changed to remove blue OLEDmaterial illumination and, in one example embodiment, replace blueillumination with green illumination. For example, a color shift ofapproximately 2% is applied gradually in a manner that the end userwould have difficulty perceiving. When the shift from blue to greenillumination is applied in a passive display zone, the end user impactis negligible and may instead help to emphasize the active display zone,which continues to present base compensated pixel values. As analternative, blue illumination may take place at a lower refresh rate,which applies less wear on the blue OLED material. In another exampleembodiment, a display zone may have overall brightness diminishedgradually over time, such as by reference to a timer that graduallydecreases illumination at a rate not perceptible to an end user. In oneembodiment, the gradual change in brightness, color or refresh rate maybe supported in part with eye tracking or other sensors that determineend user focus on content display zones and passive display zones.

Compensation image generator 84 and compensation engine 86 cooperate toprovide a measured update to compensation table 76 that provides moreaccurate and meaningful thermal and power management. Compensationvalues of compensation table 76 are applied to adjust current applied topixels based upon degradation of OLED material, and the applied currentrelates not only to the illumination that is created but also to thepower consumed and thermal energy released by the illumination. Toprovide a measurement of actual compensation needed at display 36 toachieve a uniform visual image presentation, compensation imagegenerator 84 creates a visual image for presentation at display 36 withdefined compensation values. An external camera captures a picturevisual image of the compensation image at display 36 and provides thecapture picture to compensation engine 86 for a comparison of thedisplayed pixel illumination against the expected illumination of thecompensation image so that a measured compensation can be determined.For example, a camera 39 integrated within an external informationhandling system, such as portable telephone, captures the picture of thecompensation image and communicates the picture to the compensationengine. Alternatively, the external information handling system thatcaptures the compensation engine may retrieve the compensation image toit to perform compensation analysis and return compensation values tothe information handling system that presented the compensation image.Compensation image generator 84 may command a uniform full power pixelillumination and measure compensation based upon actual illuminationdifference to the full power illumination. Alternatively, compensationimage generator 84 may present a compensation image having compensationvalues of compensation table 76 applied so that an error that exists inthe compensation values will show as a nonuniform visual image.

In one example embodiment, compensation engines 86 operating oninformation handling system 10 and an external camera system coordinateto aid in the accuracy of the compensation value measurement. Forinstance, a difference between a presented image pixel and a pictureimage pixel is used to determine the difference between what GPU 28commands for illumination at display 36 and what illumination isactually produced. A typical external camera captures 10 or moremegapixels in a visual image so that each pixel 60 of a compensationengine can be analyzed across multiple pixels of the picture captured ofdisplay 36; however, when pixels in proximity to each other bothilluminate, light may bleed between the pixels so that the accuracy ofanalysis of the compensation image. To help isolate pixels 60 duringpresentation of a compensation image, compensation image generators 84at the presenting and capturing systems may synchronize changes to thecompensation image over time with time stamps to aid analysis withcapture images. For instance, the compensation image may include a videohaving alternating pixels in an off state and transitioning at timestamps to an on state while illuminating pixels transition to an offstate. As an alternative, each pixel color may illuminate separatelywith alternating red, green and blue pixels so that each pixel'smaterial for each color is separately measured and the different colorshelp to separate illuminated pixels for analysis. In one embodiment, awireless communication between the systems provides a live feed ofcaptured pictures to the compensation engine so that a real time commandof changes to compensation image generator may adjust the compensationimage as satisfactory visual images for comparison are captured.

Referring now to FIG. 3, a flow diagram depicts a process for adjustingvisual image presentation to achieve power and thermal managementobjectives. The process starts at step 90 with definition of pluraldisplay zones at the display. As described above, the display zones maybe defined to achieve various objectives based on system configurationand content presentation. At step 92, monitoring is performed for powerand thermal conditions that are subject to management by adjustments isdisplay presentation of visual images. For instance, a low batterycharge might initiate a power saving constraint. Similarly, a skintemperature nonuniform condition may initiate a thermal managementconstraint. At step 94, a determination is made of whether a thermal orpower condition is detected that is associated with an adjustment tovisual image presentation at the display. If not, the process returns tostep 92 to continue monitoring for power and thermal conditions. If athermal or power condition is detected, the process continues to step 96to present visual images at the display zones with power and/or thermaladjustments, such as are described above or in greater detail below.

Referring now to FIG. 4, a flow diagram depicts a control process foradjusting power applied for presentation of visual images based uponhousing rotational orientations. The process starts at step 98 andinitiates at step 100 with transition of the information handling systemfrom an off state or standby state having the display idle. At step 102,the display screen transitions to an on state to present visualinformation with all display zones enabled. At step 104, the processwaits for end user selection of display zone management based uponhousing rotational orientation. In one example embodiment, display zonesenable automatically based upon detected housing rotational orientationangles, although alternative embodiments may use other conditions toinitiate display zones, such as power or thermal states. Alternatively,display zones may remain inactive until selected by an end user. At step106, a determination is made of whether display zones are enabled and,if so, the process continues to step 108. If display zones are notenabled, the process returns to step 102 to continue monitoringconditions.

At step 108, display zones are enabled. In one embodiment, display zonesare predefined, such as by grouping predetermined contiguous pixelsbased upon detected rotational orientation. In an alternativeembodiment, display zone boundaries are defined as display zones areenabled and updated as conditions change, such as power and thermalconditions. For instance, display zones seeking to manage powerconsumption might change boundaries as selected content changes; anddisplay zones seeking to manage thermal conditions might changeboundaries as thermal uniformity across the housing skin changes. Atstep 110, the timing controller is provided with the display zones bythe display driver through the graphics processor, and at step 112 thevariations in illumination for each display zone are applied based uponthe detected housing rotational orientation. At step 114, the displayscreen presentation of visual images is adjusted in each display zonebased upon viewing angle by using the graphics processing unit threedimensional look up table of display compensation values. As describedabove, various embodiments may enforce different display zone logic toachieve different display objectives. In some embodiments, the timingcontroller and graphics processing unit cooperate to apply adjustedpixel values in an efficient manner that avoids disruption of presentedvisual images. The process then returns to step 108 to continuemonitoring the display zone configuration.

At step 108, if the process detects a condition or command to cease theuse of display zones, the process continues to step 116 to disable theselected display zones. At step 118, the process retrieves the defaultdisplay screen lookup table values and applies those values to thedisplay visual image. The process then continues to step 114 to adjustdisplay operations based upon rotational orientation and the defaultdisplay settings. In alternative embodiments, adjustment of the displayto default settings may impact other power and thermal managementprocesses. For instance, transition to default display logic mayincrease power draw and display zones having partial pixel densityreturn to full pixel density that has increased power consumption andthermal release.

Referring now to FIG. 5, an example of an OLED display 36 depictsdisplay zones 120 having content window 38 and power managementconfigurations. In the display zone 120 having content window 38, visualimages are presented with the base compensated pixel values providedfrom the graphics processor. That is, content window 38 is presentedwith visual qualities selected by the end user through display settingsand adjusted by compensation values to correct for OLED materialdegradation. The base compensated visual images present content window38 with visual characteristics intended by the end user. In the exampleembodiment, power management is provided at a display zone 120presenting background 42 visual images. The background 42 visual imagehas a partial display density with every other pixel placed in an offstate to reduce power consumption without excessive impact on visualquality. In one example embodiment, the off state is enforced by thetiming controller by cutting off current to the off state pixels.Periodically, the timing controller shifts the on pixels to an off stateand the off pixels to an on state to encourage level degradation of theOLED material. In alternative embodiments, other types of adjustmentsmay be applied, such as using decreased pixel brightness instead of anoff state or scanning a refresh at only the pixels in the on state. Inan alternative embodiment that addresses thermal management, pixels maybe selected for the on state and off state based upon thermal conditionsat the information handling system where the off state will reducethermal release by display 36 and the on state will increase thermalrelease.

Referring now to FIG. 6, a flow diagram depicts a process for managinginformation handling system skin temperature by adjusting display zonepixel illumination. The process starts at step 122 and continues to step124 to retrieve a temperature zone map of the information handlingsystem housing skin temperatures, such as based upon temperatures sensedby thermal sensors disposed around the housing. At step 126, adetermination is made of whether any portions of the temperature zonemap are too hot. The thermal constraint may be an absolute maximumtemperature or may be a nonuniform temperature condition having toolarge of a thermal gradient across the display. For instance, disparatetemperature distributions can impact the quality of illuminationpresented across a visual image as OLED material responds differently atdifferent temperatures. If the thermal constraints are not exceeded, theprocess continues to step 130 to operate the display in a base mode,step 132 to update the time, and then to step 124 after a predetermineddelay, such as 60 seconds. If at step 126 the temperature is too high,the process continues to step 128 to adjust the display refresh rate andupdate the lookup table for compensation that will provide a uniformbrightness at the detected thermal conditions and refresh rate. Invarious embodiments, refresh rate may be adjusted across the entiredisplay or in an individualized manner in separate display zones totarget a desired thermal state. The process returns to step 124 after a60 second delay to continue monitoring the thermal state until the base.In alternative embodiments, alternative illumination of display pixelsmay be applied to manage thermal conditions. For example, a partialpixel density may be used that changes the ratio of pixels on versus offso that a thermal state of the display is achieved.

Referring now to FIG. 7 a flow diagram depicts a process for managingpresentation of ghost images at an OLED display by adjusting colorpresented at the display. In particular, some parts of the display, suchas the tool bar, tend to show the same image for an extended timeperiod, such as a trash or quick start icons, so that OLED materialdegradation can cause the image to ghost on the display even when notselected. To minimize the impact of static images, a timer and estimateof end user activity level applied to gradually transition from a baseor commanded color to an off color that offsets the ghosting. Theprocess starts at step 134 and determines if a desktop user applicationprogramming interface (API) is active at step 136 or a static desktop ispresented at step 138. If so, the process continues to step 140 torearrange pixel coloration. Generally, blue OLED material tends todegrade at a more rapid rate than other colors so that pixel colorationwill typically bias away from blue and towards red or green, althoughpixel color may bias towards blue in some instances. At step 142, theselected color is faded in small increments that make the changes inappearance to the visual images imperceptible to an end user, such asincrements of 10% or even 2%. At step 144 the look up table referencedby the graphics processor and/or timing controller is set to maintainthe selected color and the process ends at step 146. In the exampleembodiment, color fade may be managed over a display as a whole, adisplay zone or a particular image, such as an icon.

Referring now to FIG. 8, a flow diagram depicts a process for adjustingthermal and or power constraints associated with an OLED display byadjusting perceived brightness at the display. The process seeks toenforce adjustments to presentation of visual images for thermal, powerand other considerations in a manner imperceptible to an end user. Basedupon an end user's interactions, such as end user proximity, gaze andinputs at I/O devices, display refresh rates, contrast settings andbrightness are adjusted gradually over time. Although contrast istypically defined as white and black levels in a display visual image,however, blue, red and green color mixtures also give high contrast.Selectively allocating these colors at OLED pixels will adapt contrastwhile offering reducing blue OLED material degradation and decreasingpower consumption. Based upon end user position and selected content, asthe user defocuses a low refresh rate change to a high refresh rateadapts the visual image to the contrast change. The process starts atstep 148 with sensor detection of the end user eye and/or pupil movementto indicate the portion of the display in focus. At step 150, visualperception of an end user to changes in visual image presentation aredetermined as a function of time and image brightness. Applying the timeand brightness function, at step 152, pixel color allocation is adjustedto minimize usage of blue pixels gradually over time while the imageremains static. At step 154, brightness is controlled from a high valueto a lower value gradually over time in a manner imperceptible to theend user. In the example graph 156, the changes to color and brightnessimplemented gradually over time are depicted for an example embodimentthat performs changes in brightness and color contrast in incrementsover time. Generally, adjustments to display visual image presentationas described above with respect to power and thermal management may alsobe performed in this graduated manner for display zones.

Although the present invention has been described in detail, it shouldbe understood that various changes, substitutions and alterations can bemade hereto without departing from the spirit and scope of the inventionas defined by the appended claims.

What is claimed is:
 1. An information handling system comprising: ahousing having first and second housing portions rotationally coupled bya hinge; a processor disposed in the housing and operable to executeinstructions to process information; a memory disposed in the housingand interfaced with the processor, the memory operable to store theinstructions and information; a display integrated in the housing andhaving plural organic light emitting diode (OLED) pixels, the displayoperable to present visual images by illuminating the OLED pixels basedupon a pixel value; a graphics processor interfaced with the processorand display, the graphics processor operable to process the informationto generate pixel values that define visual images for presentation atthe display; a compensation image generator operable to present acompensation image at the display having a predetermined luminance andcolor; and a compensation engine stored in non-transitory memory andhaving instructions that execute on the processor to receive a cameraimage taken by an external camera, the camera image capturing thedisplay presenting the compensation image, the instructions furthercomparing the camera image and the compensation image to calibrate colorand luminance presented at the OLED pixels .
 2. The information handlingsystem of claim 1 wherein: the external camera interfaces with thecompensation image generator and the compensation engine to coordinatethe presentation of the compensation image and capture of the cameraimage.
 3. The information handling system of claim 2 wherein thecompensation image comprises alternating illumination of pixels spacedbetween one or more pixels in an off state and the camera imagecomprises a video captured over a predetermined time period.
 4. Theinformation handling system of claim 3 wherein the compensation imageand video each include time stamps applied by the compensation engine toassociate pixel location and pixel illumination.
 5. The informationhandling system of claim 1 wherein the compensation engine appliescompensation values to pixel values generated by the graphics processorto apply compensated pixel values to the display that compensate fordegradation at the pixels.
 6. The information handling system of claim 5wherein the compensation image generator provides pixel values to thedisplay without compensation by the compensation values and thecompensation engine determines a compensation to adjust the pixel colorand luminance to a predetermined value.
 7. The information handlingsystem of claim 5 wherein the compensation image generator providespixel values to the display with compensation by the compensation valuesand the compensation engine determines a compensation to adjust pixelcolor and luminance based at least in part upon the compensation values.8. The information handling system of claim 1 wherein each OLED pixelincludes a red, a green and a blue OLED material and the compensationimage generator presents compensation images having only red OLEDmaterial illuminated, only green OLED material illuminated and only blueOLED material illuminated.
 9. The information handling system of claim 1wherein the display comprises a folded OLED film extending over opposingsides of the first housing portion.
 10. A method for compensating aninformation handling system display presentation of visual images, themethod comprising: generating a compensation image at the display havinga predetermined luminance and color at each of plural organic lightemitting diode (OLED) pixels of the display; capturing a camera image ofthe display presenting the compensation image, the capturing performedby an external camera; comparing the compensation image and the cameraimage to determine calibration information that calibrates color andluminance presented at the OLED pixels; and applying the calibrationinformation to adjust the color and luminance of the OLED pixels forpresentation of content as visual images.
 11. The method of claim 10further comprising: interfacing the information handling system and theexternal camera; changing the compensation image over time; and storingsynchronizing information with the camera image indicating the changingof the compensation image.
 12. The method of claim 10 wherein: thecompensation image is generated without application of the calibrationinformation; and the comparing determines a full difference betweencolor and luminance available from degraded pixels and color andluminance available from compensated pixels.
 13. The method of claim 10wherein: the compensation image is generated with application of thecalibration information; and the comparing determines a partialdifference between color and luminance as calibrated at the degradedpixels.
 14. The method of claim 10 wherein the compensation imagecomprises a video having alternating colors presented at the plural OLEDpixels and changing at a predetermined periodic interval.
 15. The methodof claim 10 wherein the comparing is performed at the informationhandling system by communicating the camera image from the externalcamera to the information handling system.
 16. The method of claim 10wherein the comparing is performed at the external camera bycommunicating the compensation image from the information handlingsystem to the external camera.
 17. The method of claim 10 wherein thecalibration image comprises a video having every other of the pluralpixels illuminated in a periodic manner.
 18. The method of claim 10wherein the calibration image comprises a video having alternating red,green and blue pixel illumination.
 19. A portable information handlingsystem comprising: a processor operable to execute instructions toprocess information; memory operable to store the information andinstructions; a camera interfaced with the processor and operable tocapture an image of an information handling system having an integratedorganic light emitting diode (OLED) display presenting a compensationimage; a communication medium operable to communicate with theinformation handling system having the integrated OLED display; and anon-transitory memory operable to store instructions that execute on theprocessor to: retrieve through the communication medium a compensationvisual image presented at the OLED display; capture a calibrationpicture of the OLED display with the camera; compare color and luminanceof the OLED pixels detected in the calibration picture with color andluminance of the compensation visual image to determine calibrationinformation defining adjustments to pixel values applied to the OLEDdisplay; and communicate the calibration information through thecommunication medium.
 20. The portable information handling system ofclaim 19 wherein the compensation visual image comprises pixel luminanceand color at a greatest available setting.